Thread: A Lemon set?
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Old 04-03-2013, 08:19 AM
dieseljeep dieseljeep is offline
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Quote:
Originally Posted by Einar72 View Post
I don't wanna go too far out on a limb having not seen the schematic, but there may not be enough performance engineered into the poor old thing to not have some buzz. I think it was Zenith that had a pot somewhere in their design called a "buzz control". The usual cause of buzz on white-intensive video (like text) is the strong white-level signal "spilling over" into the sound circuit. I wouldn't expect the poor little Muntz's AGC circuit to handle the overmodulated video signal from a modern VCR/DVD/Cable Box/NTSC Converter modulator, try an attenuator on the antenna input, since there's no more need to have weak-signal capability...
Zenith sets had a buzz control because of the type of audio detector circuit they used.
You're right regarding, attenuating the signal. Muntz didn't use much of a AGC circuit. They seemed to run the IF and RF "wide open".
You also had to try several different 12AT7's and 6BL7's to get those circuits to work properly.
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